import numpy as np
A=np.array([1,2,3,4])
print(A)
print(np.ndim(A)) #数组的维度
print(A.shape)#返回一个元组
print(A.shape[0])#元组的第一个元素

B=np.array([[1,2],[3,4],[5,6]])
print(B)
print(np.ndim(B))
print(B.shape)
print(B.shape[1])